Short-circuiting device



Oct. 29, 1929. w. J. BI QANSON ET AL 1,733,216

SHORT CIRCUITING' DEVICE Filed Oct. 23, 1926 IN V EN TORAT 7 ATTORNEYS.

Patented Oct. 29, 1929 UNITED STATES P ATE-NT o FFicE WALTER J. BRANSON AND EDWIN M. WE G T, 'oE srnrnerrn Ln, oriro, nssreuons, BY MESNE ASSIGNMENTS, TO ROBBINS & MYERS, me, or SPRINGFIELD, 01110, A

CORPORATION OF OHIO SHORT-CIRCUI'I ING DEVICE Application filed October 23,

This invention relates to short circuiting devices for electric motors, particularly motors of the repulsion induction type.

In short circuiting devices of this kind there is employed a movable contact which is forced against the commutator bars by centrifugally operated devices. It has been usual to so mount this movable contact device that when in short circuiting position a current will flow through the various parts with which it is associated including the bearings for the motor shaft and the cam surfaces between the contact devices and centrifugally operated devices which result in mechanical injuries to these parts.

The object of this invention is to so mount the movable contact device that it is insulated from the structure upon which it is mounted to thereby prevent injurious currents from circulating through the structure with the injurious results stated.

In the accompanying drawings:

Fig. 1 is a longitudinal section of a short circuiting device to which the invention has been applied.

Fig. 2 is an enlarged section of a portion of the same.

Fig. 3 is an elevation of the short circuiting disk and its insulation.

Referring to the drawings, 1 represents the motor shaft, 2 the commutator, 3 a collar mounted on the shaft in a manner to rotate therewith, 4 a sleeve slidably mounted upon the collar, 5 a cup-shaped casing secured to the outer end of the collar, 6 a plurality of segmental weights mounted in the casing about the collar and 7 anti-friction balls carried by the weights which co-operate with an inclined portion 5 on the guard casing and an inclined flange 4 projecting from the outer end of the sleeve 4. Mounted upon the sleeve 4 against the flange 4 is a ring 8 of insulating material. This ring 8 is shaped to provide an annular shoulder 8 against which is seated a disk 9 which forms a contact member for engagement with the bars 2 of the commutator, this disk being held in position by a spring clip 10 which fits in an annular groove in the ring 8. This ring also has another shoulder 8", and between this 1926. Serial No. 143,726.

'shouldera'nda Washer 11 'i s interposed a coil creases the weights move outwardly by centrifugaljforce'and'inove the disk 9 in engagement with the commutator bars against the tension of the spring 12.

By this arrangement it will be seen that the contact disk is completely insulated from the structure which carries and operates it so as to prevent the contact disk when in engagement with the commutator bars from carrying injurious currents to the structure.

Having thus described our invention we claim:

1. In a short circuiting device, a rotatable member a plurality of weights rotatable therewith and movable outwardly by centrifugal force, a sleeve slidably mounted on said member movable by said weights by frictional contact therewith, a ring on said sleeve, and a contact device carried by said ring, said ring being of insulating material to insulate said contact device from said Weights and rotatable member.

2. In a short circuiting device, a rotatable member, a plurality of weights rotatable therewith and movable outwardly by centrifugal force, a sleeve slidably mounted on said rotatable member having an inclined face cooperating with said weights, a ring of insulating material mounted on said sleeve, and a contact device mounted upon said ring.

3. In a short circuiting device, a rotatable member, a plurality of weights rotatable therewith and movable outwardly by centrifugal force, each of said weights having a plurality of open-ended pockets, a pair of balls in each pocket in rolling contact with each other with the balls protruding slightly from the ends of said pockets, inclined members on respective sides of said. weights one of which is movable axially of the rotatable member, a spring for holding said inclined members and said balls in contact, a ring of insulating material mounted upon the axially movable inclined member, and a contact de vice carried by said ring.

shaft, a commutator mounted thereon, a housing rotatably connected with said shaft having an inner inclined face, an axially movable sleeve about said shaft having an inner inclined flange, a plurality of centrifugally operated weights mounted in said housing having an inclined portion mounted between the inclined faces of said housing' and flange, a ring of insulating material loosely mounted on said sleeve, a coil spring interposed between said ring and an abutment on said shaft to hold said ring to position, an annular shoulder formed on said ring, a disk forming a contact member mounted on said disk against said shoulder, said ring having a groove, and a spring clip in said groove to hold said contact disk in position.

In testimony whereof, We have hereunto set our hands this 22nd day of October, 1926.

\VALTER J. BRANSON. EDWIN M. WVRIGHT. 

